Tires for use in off-road applications, such as mine service tires, are subjected to conditions which require the tires to withstand punctures, especially in the tread regions. Solid-fill tires have been used in such applications. However, disadvantages of solid-fill tires include the facts that they generally run hotter than pneumatic tires and do not provide the cushioned ride of pneumatic tires.
Alternatives to solid-fill tires have been proposed in the art. For example, U.S. Pat. No. 3,022,810 to Lambe discloses a tire and rim combination wherein the cavity between an inner surface of the tire and the rim may be partially filled with a resilient foam. Generally, the resilient foam is said to adhere to the wheel rim to form an air-tight seal. The foam may allegedly be prevented from adhering to the wheel rim at certain points to allow the introduction of compressed air through the wheel rim. The foam is compressed in the presence of introduced air or expanded to fill the cavity in the absence of air.
U.S. Pat. No. 4,197,893 to O'Coin discloses a reusable shield for use within a tire casing. The outer surface of the shield mates with the inside surface of the casing and the inner surface of the shield is contoured to minimize the thickness at a flex point of the tire in order to purportedly reduce heat build-up and fatigue. A base ring fills the space between the wheel rim and the shield. Alternately, a pneumatic tube can be used in place of the ring. The outer surface of the shield does not adhere to the inside surface of the casing in order to allow removal and reuse of the shield. The shield is molded by fitting the base ring between a casing and a wheel by cutting a slit in the ring. The ring is also equipped with pull tabs to assist removal. An opening passage is formed through either the ring or the casing. Liquid urethane is then injected between the ring and the casing under pressure and allowed to harden. There still exists a need in the art for a tire and method of producing such for use in off-road applications which provides puncture-resistance, especially in the tread region, which provides better performance than solid-fill tires.